Islands and Protected Areas of the Gulf of California

• Official name: Islands and Protected Areas of the Gulf of California
• Location: Mexico
• Type: Natural
• Year of inscription: 2005; 2007 extended

The Islands and Protected Areas of the Gulf of California is a United Nations Educational, Scientific and Cultural Organization (UNESCO) Natural World Heritage Site because it is among the world’s most ecologically intact ecosystems. It is home to hundreds of species of fish, invertebrates, cacti, and reptiles, as well as significant populations of marine mammals, including many cetaceans. The region was inscribed on the World Heritage list in 2005; two years later, it was expanded with the addition of two national parks: Islas Marías and the Archipelago de San Lorenzo.

The site is in northeastern Mexico in the Gulf of California and consists of ten protected areas. The northernmost boundary is at the Colorado River delta, while the southern border is 168 miles (270 kilometers) southeast of the tip of the Baja California Peninsula, encompassing a range of 870 miles (1,400 kilometers). It consists of eight island groups comprising 244 islands and islets, as well as coastal areas. The total area is more than 1.8 million hectares, 76 percent of which is sea. The site consists of several oceanographic zones, namely the Upper Gulf; the Great Islands with the San Lorenzo Archipelago and Isla San Pedro Mártir; the Central Gulf with el Vizcaíno and Bahía de Loreto; and the South, including Capes Pulmo and San Lucas.

The area is significant for researchers due to its unique qualities. Nearly all major oceanographic processes are taking place there. It supports about seven hundred species of vascular plants, or those with vascular tissues, which are conductive and move water and nutrients. The Islands and Protected Areas of the Gulf of California is the largest collection of any other marine or insular site on the World Heritage list. It contains nearly one thousand fish species, 39 percent of the total number of marine mammals on Earth, and one-third of the marine cetacean species, which includes dolphins.

History

The Gulf of California is about 4.5 million years old. Between 17 and 25 million years ago, the peninsula started to move away from the continent due to tectonic movement, a process that continues and has revealed fossils in the northern gulf. This movement created the Gulf of California. The Baja peninsula, which is on the Pacific plate and separates the gulf from the Pacific Ocean, is primarily mountainous. The climate of the gulf is primarily continental rather than oceanic due to this natural barrier. Most of the islands and islets are of volcanic origin. The site includes coral reefs, coastal wetlands, mudflats, desert, and deciduous forest. Plant life also includes mangroves and cacti.

The region’s protected status dates to 1993, when the Alto Golfo de California y Delta del Rio Colorado was designated a UNESCO Man and the Biosphere (MAB) site. The islands of the Gulf of California were designated a UNESCO MAB Biosphere Reserve in 1995. Over the years the site expanded, with twenty-one sites in or adjoining the World Heritage sites or declared Ramsar Wetlands of International Importance between 1996 and 2008.

The entire marine area and most of the islands are federally owned. Only a few islands are inhabited, though a few small villages and fishing camps exist. The Seri Indigenous peoples own Isla Tiburón, or Shark Island, which is not inhabited but is regarded as sacred and used for ceremonies. One island, María Madre, has been operated as a state penitentiary since 1905. Some commercial operations in the past have involved harvesting bird guano, which was sold as fertilizer. The Seri peoples have collected eggs of various bird species.

The International Union for Conservation of Nature classified the conservation outlook of the Islands and Protected Areas of the Gulf of California as critical in 2020, and it remained so into the middle of the decade. This represents an escalation since 2017, when it was rated of significant concern. The primary threats at the site and throughout Mesoamerican coastlines and islands are climate change and fishing.

Unsustainable fishing practices threaten the region’s biodiversity. Critically endangered species include black sea bass and totoaba. The latter is harvested by illegal fishing operations for sale to the Chinese market, where the swim bladder is prized as traditional medicine. Because some communities in the region rely on the black market for the swim bladders, conservation efforts have had mixed results. While researchers and governments recognize the urgency of preserving the wildlife and habitat, economic concerns in the region have not been sufficiently addressed and corruption is a significant problem. Some proposals encourage the development of ecotourism, which brings much-needed revenue and can reinforce the necessity of preserving the area. However, recreational facilities constructed in the region have had a negative impact on the mangrove habitats, and pollution has increased in the twenty-first century. The effects of climate change on corals and coastal wetlands are the subject of much study.

Significance

The site’s inscription as a World Heritage site is based on three natural criteria: VII, IX, and X. Criterion VII pertains to the property’s natural beauty. It cites the nature of the islands, which have sandy beaches and in many cases cliffs. It also refers to the diversity of birds and marine life. The site is also valuable in that the clarity of the water draws divers. Criterion IX notes that the site is densely populated with various islands—bridge and oceanic—and nearly all the significant oceanographic processes are occurring in the property. This makes the property of high value to researchers and organisms living there. Bridge islands, also called land-bridge islands or continental islands, are those that were connected to the mainland when sea levels were lower during glacial periods. Therefore, they have a higher density of species than would be expected for the area of land and are home to species that evolved from mainland species. Oceanic islands are those on which species originated by air or water, such as by seabirds or sea lions. Criterion X pertains to species diversity. This site is home to nearly seven hundred species of vascular plants, more than any other World Heritage marine or insular property. It also hosts nearly nine hundred species of fish, including ninety endemic fish, or those found only in this region. About one-third of all cetacean species are found here, as are 39 percent of all marine mammal species. Major proportions of the world’s populations of black storm petrel, blue-footed booby, and Heermann’s gulls exist on some of the islands. The site also consists of serial world heritage properties, which are those with two or more distinct areas that are geographically separated but included in the world heritage site. One of the serial properties on this site is a Sonora Desert ecosystem. The Sonora Desert is one of the world’s most biodiverse desert ecosystems.

The region is significant to the approximately eight million people who live along the Gulf of California. Among these are Indigenous groups and commercial fishing operations that support the local economy. Net fishing has had an impact on marine species, including the vaquita, the world’s smallest cetacean. These marine mammals and other creatures, such as turtles, get entangled in trawl nets used to catch shrimp. These unwanted catches, called bycatch, can drown. Furthermore, fishing operations sometimes cut loose and abandon nets, which entangle and kill various marine species. Cetaceans include dolphins, porpoises, and whales. Vaquita, which are small porpoises also called gulf porpoises, live only in the northern region of the gulf and are often caught in nets used by illegal fishing operations in this protected area. The species is critically endangered. A report for the Mexican government estimated fewer than two dozen were alive in 2018, while in the earlier 2010s the population may have been as small as ten vaquita. In 2024, the International Fund for Animal Welfare reported the vaquita population numbered between eight and thirteen, making it one of the most endangered marine species on the planet. Researchers estimate that up to half of the population is killed each year in nets. It is one of five dolphin species in the area. Many species are drawn to the gulf to feed on small fish, which thrive on the nutrient-rich waters rising from the deep. Eleven whale species, including the endangered blue whale, visit the northern Gulf. The basking shark is another species found in the region that is classified as vulnerable.

Some species are endemic to the area, and in some cases to particular islands. Almost half of the 115 reptile species are endemic, as are many of the macro-invertebrate species in the intertidal zones. Migratory bird species visit the region. About ninety species of fish are exclusive to these waters.

Bibliography

Arreola-Alarcón, I. Montserrat, H. Reyes-Bonilla, J.S. Sakthi, Francisco Rodríguez-González, M. P. Jonathan. “Seasonal Tendencies of Microplastics Around Coral Reefs in Selected Marine Protected National Parks of Gulf of California, Mexico.” Marine Pollution Bulletin, vol. 175, Feb. 2022, DOI: 10.1016/j.marpolbul.2022.113333. Accessed 11 Dec. 2024.

Del Valle González-González, L., et al. “The Espiritu Santo Island as a Critical Area for Conserving Batoid Assemblage Species Within the Gulf of California.” Environmental Biology of Fishes, vol. 104, 2021, pp. 1359–1379, DOI: 10.1007/s10641-021-01165-w. Accessed 11 Dec. 2024.

“Islands and Protected Areas of the Gulf of California.” World Heritage Centre, whc.unesco.org/en/list/1182. Accessed 11 Dec. 2024.

“Islands & Protected Areas of the Gulf of California.” World Heritage Datasheet, May 2011, world-heritage-datasheets.unep-wcmc.org/datasheet/output/site/islands-protected-areas-of-the-gulf-of-california. Accessed 11 Dec. 2024.

“Islands and Protected Areas of the Gulf of California.” IUCN World Heritage Outlook, 4 Dec. 2020, worldheritageoutlook.iucn.org/explore-sites/wdpaid/902481. Accessed 11 Dec. 2024.

“IUCN World Heritage Outlook 3.” International Union for Conservation of Nature, Nov. 2020, portals.iucn.org/library/sites/library/files/documents/2020-035-En.pdf. Accessed 11 Dec. 2024.

“Vaquita Habitat Now Listed as ‘World Heritage in Danger.’” Mongabay, 10 July 2019, news.mongabay.com/2019/07/vaquita-habitat-now-listed-as-world-heritage-in-danger. Accessed 11 Dec. 2024.

“Vaquitas.” International Fund for Animal Welfare, www.ifaw.org/animals/vaquitas. Accessed 11 Dec. 2024.